Any person who is in the process of becoming a bro by completing bro trials or other equal feats to achieve the title of "bro". I.e, someone who wants to be a bro but is incapable at the moment. These people might be:

1. Nerds
2. Girls
3. People over the age of 27

Bro 1: Bro, that nerd is starting to bulk up.

Bro 2: Yeah man, I think I saw him at the gym the other. With out his books!

Bro 1: Dude, he's totes a closet bromosexual.

Bro 1: Dude my friend Emily is totes one of the guys, she even hooked me up with her hot friend!

Bro 2: Nice bro, that's one of the biggest bro trials to complete. She is such a closet bromosexual!